Electrically conductive polymers are of increasing interest for a number of applications, particularly those where electrical conductivity is desired or required and where the physical property of an organic polymer would likewise be advantageous.
One technique for producing electrically conductive polymers has been the bulk mixture of conductive particles such as carbon black in a polymer until the population of the conductive particles is sufficient to carry a desired amount of current in spite of the insulating property of the polymer carrying the conductive material.
As used herein, however, the term "electrically conductive polymer" refers to organic polymers that can be made intrinsically conductive without the addition of metal or other conductive fillers. Such polymers offer the properties of electrical conductivity along with the properties and advantages of polymers to thereby produce relatively versatile materials advantageous in a number of applications.
Certain intrinsically electrically conductive polymers are given their electrical conducting properties through a process known as "doping." In general, doping is a process by which the polymer is treated with an oxidizing or reducing agent for a sufficient period of time to give a partially oxidized or partially reduced material that is electrically conductive.
As used herein, the term "electrically conductive" means that the conductivity of the material as measured in ohm.sup.-1 cm.sup.-1 or Siemens/cm exceeds 1.times.10.sup.-7.
Although conductive polymers have been generally known for some time, practical applications of them have been limited because those known generally tend to be brittle, lack flexibility, abrade easily, are insoluble in their conducting states, and tend to decompose upon heating before they soften.
Therefore, one potential solution to these problems has been to attempt to blend conductive polymers with other polymers having desirable physical properties to get a resulting blend which maintains its conductive properties, but which also exhibits better physical properties. To date, however, it has been generally difficult to obtain such mixtures because the available conductive polymers were not soluble in their conducting state. As known to those familiar with conductive polymers, the resulting processes require that the conductive polymers be chemically changed to a non-conducting state, disolved, mixed with other polymers, removed from the solvent, and then redoped to change the potentially conductive polymer back into a conducting state. In turn, carrying out the doping process in a mixed polymer matrix can become complicated.
Recently, however, some progress has been reached in this particular field. In U.S. patent application No. 07/203,688, inventors MacInnes and Funt, filed June 9, 1988 for "Soluble Conducting Polymers of Poly-O-Methoxyaniline", there is disclosed an electrically conductive polymer of orthomethoxyaniline that is also referred to as "polyanisidine." Polyanisidine has the unusual advantage of being soluble in a number of relatively common organic solvents in which other polymeric materials are similarly soluble. The contents of Ser. No. 07/203,688, now abandoned, are incorporated entirely herein by reference.
As a follow-up to the U.S. patent application No. 07/203,688, now abandoned, recent progress has further been made in blending polyanisidine with other polymers, often referred to as "engineering" polymers which offer the chemical and physical properties for which polymeric materials are often desired.
Work has progressed with respect to polyanisidine and its blends, however, and there remains the need for identification and development of improved synthesis of the blends and appropriate technological applications that take full advantage of polyanisidine and its properties.